Welding is a common way to join similar and dissimilar materials in a wide range of industries. Energy for welding can be applied in a variety of ways, such as by laser or ultrasonic vibrations.
In automotive manufacturing, steel or metal, such as aluminum, are being used. There is an increasing need and challenges associated with welding various materials together.
Workpieces to be joined by welding include those for instrument and door panels, lamps, air ducts, steering wheels, upholstery, truck beds or other vehicle storage compartments, upholstery components, external parts, and engine components, for instance. Regarding engine components, and other under-the-hood (UTH) applications, for example, workpieces are configured and developed continuously to withstand hot and/or chemically aggressive environments.
Regarding external parts, such as fenders, workpieces are being developed that can be painted on an assembly line and have high heat and chemical resistance over longer periods of time. And many other potential usages in automotive applications are being considered continuously.
Some materials express unwanted gas or vapor when melted in welding. Workpieces comprising zinc can have this characteristic. These workpieces can include steel coated with zinc, for example, or coated with a combination of zinc and aluminum. Workpieces are coated in these ways to provide benefits such as to provide high corrosion resistance for the resulting component.
The unwanted vapor is highly pressurized when generated in the joint being formed and must escape the surrounding molten material. Turning to the figures, and more particularly to the first figure, FIG. 1 shows an example prior art arrangement 100 in which a first workpiece 110 is being joined to a second workpiece 120. Material melted is indicated by numeral 130. The material is melted by welding energy applied (by laser, for example) to a heat-affected zone 140 (HAZ) of the arrangement 100, and the pressurized vapor is shown by numeral 150.
In some cases, the high-pressure vapor 150 forms unwanted blow holes in the molten metal to escape, such as that shown schematically in FIG. 2 with reference numeral 200. It is also possible that vapor 150 could get trapped in the molten material as it is cools.
Previous efforts to facilitate expression of the gas from the melted material in other ways are not as effective as desired and/or are costly in terms of equipment and process.